This book, co-authored by R J Kummerfield, was apparently also produced through the University of Sydney although printed in Britain. It won't be easy to find but is a lucid, thorough description of C programming on Unix pre-ANSI. The historical usefulness is in the reliance on common features of System V and 4BSD going back to Version 7! As an aid to working with old systems on emulators, it has been very helpful in understanding the environment and associated utilities of historial Unix and C. In many ways, this is the practical companion to The C Programming Language, not just reiterating C's aspects but demonstrating them and linking the language to the system libraries in a large and informative section. Ancient history, but worth a look if you can find it.